Cybersecurity can not be neglected by any IT based firm in 21st century! And storing important data of users and company is pretty normal nowadays. So, the sensitive data is in more threat than it ever was. Hackers from all around the globe target small and big scale companies with their malicious intent. Fortunately, there are security testers in this world; to protect your products and its users from data theft and hijacking. There are numerous security tests that exist for failproof security implementation. For e.g., penetration testing (pentest), usability testing, malware testing, vulnerability assessment and etc. Here, we intend to provide brief understanding about penetration testing and vulnerability assessment. Moreover, also give a brief about pentest vs vulnerability assessment.